Exhaust Smell coming through HVAC in a 2002 Jetta 1.8T

So, we’ve got strong exhaust fumes coming through the heating/AC vents when the heat or AC are on and the car is not moving. Once the car starts moving the fumes dissipate.



I’ve taken it to a garage, but they couldn’t find the source of the probelem. Any help would be great. Thanks.



-j